Background Hidradenitis suppurativa (HS) causes considerable morbidity. The long-term prognosis is of obvious interest to both patients and physicians. We conducted this study to determine the prognosis and risk factors in patients diagnosed with HS. Objectives To describe the long-term prognosis and the clinical course of HS and its association to known risk factors. Methods A postal follow-up survey with uncomplicated factual questions was conducted. As all of the patients were well acquainted with their long-standing disease, this was thought to be sufficient for meaningful results. All cases were diagnosed by a dermatologist. Overall, 212 patients diagnosed with HS between 1981 and 2001 were studied after a median follow-up period of 22years (range 12-32). Results The overall response rate was 712%, with 608% (129/212) valid (fully completed) questionnaires. Remission was reported by 394% (50/127) and improvement by 315% (40/127). Unchanged severity was reported by 205% (26/127), and 87% (11/127) experienced worsening disease. Tobacco smoking was reported by 922% (119/129). Among nonsmokers, 40% (35/88) reported remission vs. 29% (17/59) of active smokers. A higher proportion of nonobese patients (45%) reported remission than obese patients (23%). Conclusions We found that 394% of the sample reported remission of HS. Suspected risk factors appeared to influence the prognosis. Smoking and obesity were significantly linked to a lower rate of self-reported remission. The notion that lifestyle factors play a role in HS appears to be supported by this survey.